SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cd097176cb2c943d6957d6ee9adc2e116372f6e8484377b96aa8ac4773ef8fb' 
  AND token = 'K6CgRQWXEBVWrJnPTL9Uy05zbZ4lTLpj8cVE8cr47nY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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