SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0851033e6604a1ca42f18d4a39a71b39a07e80315f6d918f14144734a35e3336' 
  AND token = 'g1EI9oAAkVNU5kV2rxBUhz5VEotM+OjiFefr8VeSrk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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