SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79d422de109da673011906f9a18f68207e1eb3f2d9788788481642d5795db90a' 
  AND token = 'tIAHDpSmXqryIPDSB7HGFcZACot16Fa3dhVfWnbnu8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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