SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f81087bfdda756cd49ca694bdcf7cb9a62c2491c3dd45a4a3b3063ad1513739a' 
  AND token = 'o78awmwUq5qc373dQjz48NSRAm1jsF0c0wpyQze4K7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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