SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3e009fc4af826e165bd13e32fb612023e1bebccb7ecad319afe3b34321eb783' 
  AND token = 'rqonCTTzYP7IKFPwRpDmDuBa08GhwD+c1RYmh3wY204=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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