SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a9eedf57421a15f66545f3b5806a25bd1653d4cd778b37713254701d129c3ed' 
  AND token = '3hpZCEvzDuaxXHYHG2vzQyaHGr40Ozo+AwM62xpBrrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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