SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a6848185bc27469524dd744695d560ec5157b0bee7725a475b3483a2018c68bf' 
  AND token = 'rIqNOrOpSVV2qTHPXx/z4OPoR5G4Az+DhTlfJHSHuwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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