SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b95108adec2e3a9d30c48c61df4a41cf61a5d3352297db2f7e7ca261b981db92' 
  AND token = '5IpuoDPIRtqcm1NC4AaYHrnbB5dUjyMRIUnwUVHG4LU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}