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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26715d48a50208b32a5729eda19cbb2c187ebe0e6847a444dd6d2f39d52d8a29' 
  AND token = 'EZ5YnfjbQsQHDDoZOohlQurFOGPqXdeoiAkiUni7N0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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