SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b5209261042fdb7bd0f8b1d394cdef766338efef6a15d90ace5bc83d05f6210' 
  AND token = 'n6jBiEHX+MuQH4I2op0sQRA5vYNuJvNwDq2QYKRlp8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}