SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5f706b6a4c2dc4bd7587d759edf5df1d8673fa978452d1a131168a2a661095d' 
  AND token = 'dOBE8vsb78uG7tsjxg2f0qX+z26bJuFUGWCzhQcyhv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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