SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84ba52e71ff2dba18c7dde280c6adf763384e38e3121e5ad413d9d614897a108' 
  AND token = 'HjjfrjRFCHH4+5khFY5Onu1UtlKyJ7lTv4OT/HoIPrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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