SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f23aa51495b1a9070f0f91a97c2f66405cfcebd39aa6b4dc8f32f052773d99bc' 
  AND token = 'U0hGUFHNgc3nnRv/ZKWePN6lAk2WltYere/FQy4ZnVk=' 
  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"
    }
  }
}