SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e479779e9bfc3172952635d8437c5d811cce9a5671ba7ee48268849d99291c4' 
  AND token = 'HKgTSEisrR1pGMRhbIu2I+naYFvxbsDVzu+yZV6SaC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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