SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '438c748a98f40c52014efe86dbf12d2a0492884a79bd4cccbab54f16080da58b' 
  AND token = 'e7sOmxubuSWbLxHtyb23oBBl7irWJ/waNAA5l6UlwCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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