SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f3fa4dbd3cb4ece2f4ec7c08a284fa0372d669946d394d0bc89eb0c040c2fae5' 
  AND token = 'FNu8a/jZM/BMAHkJV67sK1azBK4cpottvl0jHe3+Pkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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