SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e26fe2983877b08987a8fb76d13dbeb5c9151b00164a825d4a8cd0908be0481' 
  AND token = 'MBhnRWNFtcRn6ob6LjW28KEPUjeAXnpnR+4puYL37hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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