SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5ea466f529b6b3f5c02c6d69c4801d0fba7fa2083dbb83a58be4aa187328b90' 
  AND token = 'Dp2itO4T4RvcF23NGkHvr5LDzAqE3tQzynW6Xhhw8GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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