SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2763b5ef35cdfc6bc251b5136b15aacc39f324a51cd87553b934050d178b4c78' 
  AND token = 'wo/HZdGgnT/GlhSYWXyd6DtR5iSqs2G41u9z7uMyidI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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