SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b945c86fb5fa9a1d3e804d465aa15d6d669b0bd53b093404bea984aba63af99' 
  AND token = '1ctfA3aJtojpq/oXujxD1xzvhRIa66E4sWx76FroCaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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