SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d29120bf10c1275a53ad04f24c362bf1720fde17217e9195aa526a87cf57a4c' 
  AND token = '/p0/+X91FdXYqcqZmqnSTi40Jw3TzQ23jvil+ewQMXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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