SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc25766a1df7accf0de1f8e59e83c78174f22ce22c9de320a6d2a3b532c11126' 
  AND token = 'WBylLLm8mKEtCj7NECGVWPOnoxIV6iiSwj+l0uUGHRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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