SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4f977a756c9eafbfa872b3624c97a1ea78bd504e2b866392a87af460253b5686' 
  AND token = 'rlc29FQ8dusm30PvN/sTYPGG/zS/rt1eEQWAN1ASR2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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