SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ef712c7be53c21d3312da890e2294cfb10b5389ee204630097783d0cafbff6a' 
  AND token = 'Je3+JWVL2Ijz9M/Yu7E9rgLebdtELm2xNFeZWFmQgBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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