SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cbf72ae777569a07b9176ef6d6ffeea90e23a2e25711b86c964c316f661223b' 
  AND token = 'lTlUhHlVPEdiEgSrrOrAzySn2mEBlV6o9fkaQF2vNFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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