SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1bf61ce50066b5ca257d887489b434ccd45e17238a41981570c1631218dc2b45' 
  AND token = 'uZFGbSjsWwjyApuFdcvvl+meZa2evhSueceHtrx1n3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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