SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2880529665d1d3d549552c65531c2d6ed8483bbce8f862ef027302791fe00542' 
  AND token = '1ejKT0Vp4rJOXoxF2gakjy33QPl/EU89eulRRKeCLkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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