SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50fafe6b2640e2df47f7d6042b31deee1c03a602d22bccb505e193c54ec31db2' 
  AND token = 'MDmK2EejCynFSPCJySFlGwXQzgj/rA8P8G1U7WFN9bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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