SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e08f1da955b441dc4471fb3289069e2830c1e01381463dc5a79d3279562f75f' 
  AND token = 'R3+8xTgARsyoMRWFUeiLvzjkVXCZjWX2nUN5gQlYmrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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