SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74486cead15262f2a043e8fce1410ae62e84fff4ba6cb5fa58854a8eb31fbed8' 
  AND token = '/bvdtdmicNb1JWHdk0Ck9sfZfHBGwRdVjoAYVpawOGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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