SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac3c9708d5f91d4b3f614c2c8e51e481ee7469630366d87f97154215b4f3a62e' 
  AND token = 'bdMz/glYs6XpklkQ5zXZvnvioSGlO7ixkVfUhb6JbMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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