SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11df03bd1b744ab58f17fbd2d3a234c728446a47bdf284f8c19ce566686dfeb7' 
  AND token = '0YuqifmqSoNz9DFENHkNs+PgVpBrqMsLUjjqgcSP4pg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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