SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a612147103156bb053048596328c36e5eb5e1e25f98f65bfaad025c2f814ba4' 
  AND token = 'dBJ2CkTSCF/BMZJGj+Uzb+wWWs5bMbCAMHBOnVzGlYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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