SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c52320dac11665b987556db0404236ce863254845b3bc26c677b97919834108e' 
  AND token = '34UBS85vUpGPJeerVSe4zbyM1NrIIomOwm4y/AKt51k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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