SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bd4c44f916a058357a4a9212db1074bda8f91db66516775103110aacae55a8d' 
  AND token = 'PGyfInk/KbsaXT/hADILHWTtTpoYwfPQhtW0KvkFTAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}