SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da4c939a12f7a82f282f81a128a6787a85679ff02368964f7809070df7da3495' 
  AND token = 'dS2Oxc4tlqe/inQeLL4v8mtjrO3RBF2chq4Mx45ow+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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