SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '909932b4c754b90b181437525d31278cd492ce6f02c2b708c30ba0aa0202360e' 
  AND token = '1dDxhMyb+ZAmNkCcYc9edWQLqU+sIIowpEPWEqLeMik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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