SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '854746af7edbc6e5c54bf4e855c07043cc2dbaca58e5aa3252a9613aa8791c7c' 
  AND token = 'udZUlf3dLw6t2x8RSFObCq3k/rQ0To6qqg8DG2m7hNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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