SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4865c626cc774998a765280844012d042f0f3a38cad498fb703e8f4ea037a74c' 
  AND token = 'FIE9hYreY+3HmiTT3FlWiW1WJbncCt+WfpmAveueNQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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