SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '849ad657041cea244539af0cb9d13d556c07ed53f8de7067a8ce681a2b9727e6' 
  AND token = 'CcU55ahy2uRezsabxuY4XPE5m4znJAVetfkjI3HGfSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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