SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b1d8918a1dc0a6f666540108b46875fa32a11c95fd720e2a317634cb5345da32' 
  AND token = 'Zh+4RbikLTQcgsy3xVpK6uhMpHnUIeUAi1i2NorCcwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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