SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '657b51c8f6350350cd23fd4705ed0fb8b188adecd645591f2c45281a9970e4de' 
  AND token = 'uyki5SKKajz/vNfBjoRsHsKoEBUmAV4z8xDxgwTxEHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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