SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf073e1f933d00c0b20460e283b49179bb02c243ada279d6e0fd2105d5b6dc5e' 
  AND token = 'IZyAL3+YibhLbjiI3WcFFLV7jz3WsKJ0Dmrw2YqtLGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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