SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5f33e27301a4ef21ded10b696879903cd73207f392b1df3355998824910ebac' 
  AND token = 'tQ76v1CBPY67fuJlIXdpSfTIRvlB3SlHo2xbxE0Xfs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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