SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '70b66c475933e852426131d2aee4558d601d67fc94e4356da5e4b4e799b63c1c' 
  AND token = '7j/bKPMZ4/ph3Jc8im7M/SGfVyjmkgTZfikMNYZv864=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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