SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97ea5cce59526203305c10acfe18454b48e676b8839f344467a0abc47348ee8e' 
  AND token = 'x85xXHgWsblTLBsQOkcxnkT3c51u5V40jRafQl19Dmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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