SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e941ad99f5c9f5bd9da32cea55f5ad8cc222120d4392ff844e185e2532bb3f4' 
  AND token = 'yfNp8sucQa9JiZzhyMfgtuXyO2mbwemxCPXleYJtQPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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