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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df5c5623261f32b470ee8448804b040a8e13552c0f103d841df42389f44dfb93' 
  AND token = 'pHkNvFYidNTq2l6wNd/k3VzDTZ8wP8XCVHZXvIOV7Wk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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