SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb36cb5ffc07dba4d2751193680873e20086c48b96591a4d5945dc3223c2190a' 
  AND token = 'U3JH+aY/3nqDf51bF4ivV4UfnLiWOpLHMVRQa1ppNnw=' 
  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"
    }
  }
}