SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6686dee86b29f847d333a2ce88237e8815f751cd5a42c98c13fa2f5ebe1d749a' 
  AND token = '6oYlctvWfhixUY0PcStmGVUSFUgDi/+J1rPVcZCxFTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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