SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03928bb12b0ab2c7a7fc2a62d250c16d79a4a888846188635147759b85dd8019' 
  AND token = 'pF3ZHEfu+FdImtUhMrR4m+WJTZ5kXPgvORSjWkG82gE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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