SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c19d89765c2b8860286216159daefe0970f74c8d28a7e686851f143a0ab907d' 
  AND token = 'fAeI1ruYsNi6mIBqCNBhfyRPRbvEBXcKC2hLOxjFBSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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