SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b80e8a1ad70223b7fc14c9290a7e193fd55f5b5466e61edcf9a434a4a5766a58' 
  AND token = 'Mk+0Pqhq5ocffQpP2jOC2Bg/Flhi+/KJu2kE3TfYdrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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