SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '314286890b35168968e70e65262c92a58fbac6765e130527924f76989750a490' 
  AND token = 'Q9zSUjGVFHWzsFoA7SIeEZVM/L+e3c5qAV6OZUeJIiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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