SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feeb9f86a5fdeceecdfedef210a762896241c147d4d5d888344c42de9cfea57d' 
  AND token = 'IsqIRmsEMtt/jOfVYUR6pMjhd64GBZE7S1B3u25/YKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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