SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbb8ce8434b37874f96df672ba1584488d10e153d979a790fbf9ce374a981d04' 
  AND token = '+tD8VCTrFIUfhmlmydUusKtP3f2vePec0/hJsqgwbMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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