SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc88112b76b29a835e41735d2cba6c84b5615083df774bb7bf943f751a7702f9' 
  AND token = 'mARz9vg56YG/lO/07M/Swhrf0PzkkqQhVSURhHTRVRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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