SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d6522b8e2a0578c08846f2d4c23bf2e37f5a8f18b9bde5506fec8f8cdf68d9b' 
  AND token = '25uMf98R40S0H1OLPvGYIqyfuJlAY2iL2FPMO81PQNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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