SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5f54c45fe88ce8e3286bdec4d2ba575eccd25784e286a11c916dbe2711e2794' 
  AND token = 'e3I/uIroBJnQuPgMGEQsGo5RZaVtgjxx8LEEEUKg/k4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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