SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b52d35d6ac5b99b35285fce9f22bac7a45b261e84bf6b02305a72babd9ed4f47' 
  AND token = 'qLYGW1e5HNLmhi8yaPRKGhNQ8g0C3jup+cvu3Py5qzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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